Preparation of fluoroalkyl end-capped vinyltrimethoxysilane oligomeric silica/poly(tetrafluoroethylene) nanocomposites possessing a superoleophilic/superhydrophobic characteristic: application to the separation of oil and water

Original Paper: Sol-gel and hybrid materials with surface modification for applications

First Online: 04 October 2016

Received: 01 August 2016

Accepted: 07 September 2016

Abstract

Fluoroalkyl end-capped vinyltrimethoxysilane oligomer [RF-(CH2CHSi(OMe)3)n-RF; RF = CF(CF3)OC3F7, n = 2, 3: RF-(VM)n-RF oligomer] can undergo the sol–gel reaction in the presence of poly(tetrafluoroethylene) fine particles under alkaline conditions to afford the corresponding fluorinated oligomeric silica/poly(tetrafluoroethylene) nanocomposites [RF-(VM-SiO3/2)n-RF/poly(tetrafluoroethylene) nanocomposites]. Interestingly, the modified glass, poly(tetrafluoroethylene) sheet and filter paper surfaces treated with the obtained nanocomposites were found to exhibit a superoleophilic/superhydrophobic characteristic, although the original poly(tetrafluoroethylene) sheet and the modified glass surface treated with the RF-(VM)n-RF oligomeric silica nanoparticles [RF-(VM-SiO3/2)n-RF] can provide the usual oleophobic/hydrophobic and oleophobic/superhydrophobic properties, respectively. The modified filter paper was applied to the separation membrane for the mixture of oil/water. In addition, the fluorinated poly(tetrafluoroethylene) nanocomposite white-colored powders thus obtained were applied to the packing material for the column chromatography to separate the mixture of oil/water and water-in-oil emulsions. We have also studied on the reusability of the present nanocomposite particle powders as the packing material for the separation of not only the mixture of oil/water but also the water-in-oil emulsions, and the colorless oil was quantitatively isolated under similar conditions even after the use of the packing materials five times.